The present disclosure relates generally to medical devices and, more particularly, to medical sensors used for sensing physiological parameters of a patient.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In the field of medicine, doctors often desire to monitor certain physiological characteristics of their patients. Accordingly, a wide variety of devices have been developed for monitoring many such physiological characteristics. These devices provide doctors and other healthcare personnel with the information they need to provide the best possible healthcare for their patients. As a result, such monitoring devices have become an indispensable part of modern medicine.
One technique for monitoring certain physiological characteristics of a patient is commonly referred to as pulse oximetry, and the devices built based upon pulse oximetry techniques are commonly referred to as pulse oximeters. Pulse oximetry may be used to measure various blood flow characteristics, such as the blood-oxygen saturation of hemoglobin in arterial blood, the volume of individual blood pulsations supplying the tissue, and/or the rate of blood pulsations corresponding to each heartbeat of a patient.
Pulse oximeters typically utilize a non-invasive sensor that transmits light through a patient's tissue and that photoelectrically detects the absorption and/or scattering of the transmitted light in such tissue. One or more of the above physiological characteristics may then be calculated based upon the amount of light absorbed or scattered. More specifically, the light passed through the tissue is typically selected to be of one or more wavelengths that may be absorbed or scattered by the blood in an amount correlative to the amount of the blood constituent present in the blood. The amount of light absorbed and/or scattered may then be used to estimate the amount of blood constituent in the tissue using various algorithms.
Pulse oximetry readings may involve placement of a sensor on a patient's tissue, such as via an adhesive sensor, a clip-style sensor, or a sensor that may be fitted into or against a wearable garment, such as a hat or a headband. With regard to the latter, if the hat or headband is not closely fitted to the patient's tissue, ambient light may interfere with the sensor's light detection. However, such a conforming fit may be difficult to achieve over a range of patient physiologies (e.g., head, arm, leg sizes) without periodic adjustment or excessive attention on the part of medical personnel. Additionally, the hat or headband may not remain accurately positioned during the entire time the patient is being monitored due to patient movement, diaphoresis, a loss or misapplication of tension of the hat or headband, or similar occurrences. Further, an overly tight fit may cause an undesired amount of local exsanguination of the tissue around the sensor. Exsanguinated tissue, which is devoid of blood, may shunt the sensor light through the tissue, resulting in reduced measurement accuracy.